1. Technical Field
The present invention relates generally to liquid crystal light valve projectors and, more specifically, to a projector polarization system that increases the amount of usable projector light by polarizing and interleaving light beams from a projector light source.
2. Discussion
The quality of an image output from a conventional liquid crystal light valve (LCLV) projector is directly dependent upon the light contrast provided by a projector light source. Typically, the projector light source outputs a light beam including first and second orthogonal polarized components. The first component provides contrast to the images projected onto the projector light valve or valves, while the second component is considered unusable, or waste light, for light valve contrast purposes.
To provide a higher degree of contrast, light polarization systems have been developed for LCLV projectors. These polarization systems typically split the randomly polarized light beam into the above-mentioned first and second orthogonal linear polarized components, convert the second polarized component, as the first component and then recombine the two polarized light beam components for light valve illumination purposes.
Such conventional light polarization systems increase the angle of divergence of the combined polarized light beam. Therefore, the recombined polarized light beam has a much larger angle of divergence than the light beam input from the light source. The increased angle of divergence is undesirable, as the light valve prism plate is angle sensitive, and provides less contrast to the image formed on the light valve as the angle of divergence increases.
Therefore, there is a need for a light polarization system for an LCLV projector that increases the percentage of usable light input from a light source by maintaining the original angle of divergence of the light when the polarized light is recombined and projected onto a light valve through an angle sensitive prism or polarizer.